1. Field of the Invention
The present invention relates to an apparatus of diagnosing an internal combustion engine and a method of diagnosing an internal combustion engine and, in particular to an apparatus of diagnosing an internal combustion engine and a method of diagnosing an internal combustion engine wherein the internal combustion engine diagnosis apparatus has a valve mechanism in which a timing of the valve mechanism has a variable timing.
2. Prior Art
Japanese application patent laid-open publication No. Hei 4-91330 (1992) has disclosed an internal combustion engine apparatus for discriminating a variable timing control unit for troubles according to a difference between rotational speeds of an internal combustion engine by ON and OFF commands on a solenoid that varies the valve opening/closing timing.
Japanese application patent laid-open publication No. Hei 6-317115 (1994) has disclosed another internal combustion engine apparatus for judging a variable timing control unit for troubles by obtaining an output fluctuation from an engine rotation signal, controlling to turn off the variable valve timing controlling solenoid, and calculating the relationship between the output fluctuation and the overlap quantity of the intake valve and the exhaust valve.
Japanese application patent laid-open publication No. Hei 6-317117 (1994) has disclosed another internal combustion engine apparatus for judging a variable timing control unit for troubles by judging ON and OFF states of the variable valve timing controlling solenoid and comparing the pulsating level of the engine intake air which is actually measured by a preset pulsating level for the running condition.
Further, Japanese application patent laid-open publication No. Hei 7-293287 (1995) has disclosed another internal combustion engine apparatus for judging a variable timing control unit for troubles by judging ON and OFF states of the variable valve timing controlling solenoid and comparing the pulsating cycle of the engine intake air which is actually measured by a preset pulsating cycle for the running condition.
The above stated conventional internal combustion engine apparatuses for judging a variable timing control unit for troubles have had a difficulty in judging for troubles in various modes in which the intake valve and the exhaust valve overlap condition with each other while the valve mechanism is controlled not only by the intake valve but also by the exhaust valve.
An object of the present invention is to provide an apparatus of diagnosing an internal combustion engine and a method of diagnosing an internal combustion engine wherein a cycle efficiency of the internal combustion engine can be improved.
Another object of the present invention is to provide an apparatus of diagnosing an internal combustion engine and a method of diagnosing an internal combustion engine wherein a reliability of a control unit of the internal combustion engine can be assured.
A further object of the present invention is to provide an apparatus of diagnosing an internal combustion engine and a method of diagnosing an internal combustion engine wherein for trouble diagnosing a control unit of the internal combustion engine the apparatus has a valve mechanism to improve its cycle efficiency and assuring the reliability of the control unit.
The above stated objects of the present invention can be attained by an apparatus of diagnosing an internal combustion engine in which an intake valve or an exhaust valve opens and closes each cylinder of the internal combustion engine by electric signals, an abnormality in a valve mechanism and a control apparatus of the valve mechanism is diagnosed in accordance with a quantity of a backward flow which flows into an intake manifold of the internal combustion engine and an overlap open time period between the intake valve and the exhaust valve or an abnormality of a valve mechanism and a control apparatus of the valve mechanism is diagnosed in accordance with a quantity of a backward flow which flows into an intake manifold of the internal combustion engine and a preset target EGR quantity of the internal combustion engine.
The above stated objects of the present invention can be attained by an apparatus of diagnosing an internal combustion engine in which an intake valve or an exhaust valve opens and closes each cylinder of the internal combustion engine by electric signals, an abnormality in a valve mechanism and a control apparatus of the valve mechanism is diagnosed in accordance with a quantity of a backward flow which flows into an intake manifold of the internal combustion engine, an overlap open time period between the intake valve and the exhaust valve, and a rotational speed of the internal combustion engine.
The above stated objects of the present invention can be attained by a method of diagnosing an internal combustion engine in which an intake valve or an exhaust valve opens and closes each cylinder of the internal combustion engine by electric signals, the internal combustion engine diagnosis method includes steps, a first step of diagnosing an abnormality in accordance with an overlap open time period between the intake valve and the exhaust valve and a backward flow time period (Tbi) of the intake manifold of the internal combustion engine, and a second step of diagnosing an abnormality in accordance with a target EGR quantity of the internal combustion engine and a mass of a backward flow air (Qbi) in the intake manifold of the internal combustion engine.
The above stated objects of the present invention can be attained by a method of diagnosing an internal combustion engine in which an intake valve or an exhaust valve opens and closes each cylinder of the internal combustion engine by electric signals, the internal combustion engine diagnosis method includes steps, a first step of diagnosing an abnormality in accordance with an overlap open time period between the intake valve and the exhaust valve, and a ratio (Tn1/Tb2) of a forward air flow time period (Tn1) to a backward flow time period (Tb2) of the intake manifold of the internal combustion engine, and a second step of diagnosing an abnormality in accordance with a target EGR quantity of the internal combustion engine and a ratio (dn/un) of a peak forward flow air mass (dn) to a peak backward flow air mass (un).